Bedbug-detecting dog Barney signals which container has live bed bugs during a demonstration at the Bed Bug University North American Summit 2010 on September 22, 2010 in Rosemont, Illinois. The two-day conference of bed bugexperts and pest control workers featured seminars from researchers and vendors displaying the latest products focused on bedbug detection, elimination and prevention.

Photo: Brian Kersey, Getty Images

Bedbug-detecting dog Barney signals which container has live bed...

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FILE - In this file photo taken Aug. 25, 2010, a bedbug is found in a mattress at a home in Columbus, Ohio. As bedbugs relentlessly re-enter American life, and we learn how little we can do to stop them, it's increasingly important to know how to avoid them and how to cope if they work their way into our homes and belongings.

Photo: Terry Gilliam, AP

FILE - In this file photo taken Aug. 25, 2010, a bedbug is found in...

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ROSEMONT, IL - SEPTEMBER 22: Bed Bug Central public relations associate Calvin Allen shows a vial containing live bed bugs at the Bed Bug University North American Summit 2010 on September 22, 2010 in Rosemont, Illinois. The two-day conference of bed bugexperts and pest control workers featured seminars from researchers and vendors displaying the latest products focused on bedbug detection, elimination and prevention.

Photo: Brian Kersey, Getty Images

ROSEMONT, IL - SEPTEMBER 22: Bed Bug Central public relations...

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West Oakland Tires and Repairs is part of the property owned by Sang Hahn, who could be forced to sell his property as part of a change in eminent domain policy in Oakland.
The property is rented by owners of a tire shop and auto yards.

Photo: Michelle Gachet, The Chronicle

West Oakland Tires and Repairs is part of the property owned by...

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Property owner Sang Hahn stands in West Oakland Tires and Repairs, a business that would have to close if the property would be sold to the city in Oakland, Calif., on Sept. 08, 2010.

Yes, we have bedbugs in San Francisco. No, they're not taking over the city.

Bedbugs have become a major public health concern in big cities all over the country, with some of the worst outbreaks reported in New York City, Philadelphia and Detroit. The pests have been reported in movie theaters and department stores in Manhattan, and this summer they were found in the Empire State Building.

They don't seem to be nearly as widespread in San Francisco or other parts of the Bay Area, although it is difficult to say why. San Francisco public health officials say it's because they developed strict regulations to get rid of the pests when they first started showing up in the city about five years ago.

But the number of bedbug cases is on the rise in San Francisco, according to officials in the city's Public Health Department.

The number of reported cases has jumped 78 percent over the past four years, from 301 cases in 2006 to 537 cases last year. So far this year, 401 cases have been reported to the health department.

San Francisco SupervisorJohn Avalos has proposed amending existing health code legislation to include, for the first time, bedbugs in its list of violations considered harmful to the public.

Under the revised legislation, which will be heard next Monday by the Board of Supervisors' public safety committee, landlords could face stiffer fines for failing to treat bedbugs, as well as lice, cockroaches, scabies and other noxious insects.

Some entomologists say it may just be a matter of time before San Francisco has as big a problem as any other North American city.

"The biggest problems are along our coastlines. San Francisco has already been hit," said UC Berkeley entomologist Gail Getty. "It's going to get worse. We can get a handle on this, but only with education. And the problem is nobody wants to talk about it."

People don't admit it

Actually, plenty of people are talking about it. But few people - be they apartment dwellers or homeowners or hoteliers - want to admit they've got bedbugs.

Bedbugs are brownish, wingless insects about the size of a pencil eraser. They're usually flat, although they plump up after a "blood meal" - when they've fed on a person.

They feed on sleeping people and animals at night, and they live in dark, closed-in spaces, usually close to where humans sleep, so they're often found on mattresses and headboards or hiding behind picture frames or under lamps. The bugs themselves might be visible if there is an infestation, but people should also look for small, dark spots that could be the pests' fecal matter or even tiny bloodstains.

Similar to head lice, bedbugs don't actually cause much of a health threat. Their bites can leave itchy red welts, but they aren't known to transmit any human diseases. But the anxiety they cause can be just as big a problem as any disease, doctors and public health officials say.

In fact, Smith and other public health officials worry about people becoming overly concerned about the threat of bedbugs - fretting over every possible bite or losing sleep over the possibility of an infestation.

Drastic measures

Already, anxiety over infestations has led some people to take drastic measures to kill the bugs - using pesticides that aren't considered safe for indoor use and that can make people sick, for example. Getty said she's talked to people who have sprayed their own bodies with pesticides.

People who think they have an infestation - they have obvious bite marks on their bodies or they have seen bugs in their homes - should call an exterminator right away, public health officials say. It's easiest to take care of an infestation before it spreads too far.

Bedbugs were common household pests for centuries, but with the invention and widespread use of strong pesticides, they were mostly eradicated in the United States by the 1950s. When DDT was banned in the 1970s, bedbugs started to make a slow return, and within the past few years, the United States has seen an "alarming resurgence" of the pests, according to the Centers for Disease Control and Prevention.

Part of the reason for their climb out of near-extinction is that Americans have become woefully bad at killing bedbugs. The insects are resistant to many pesticides; in fact, they'd already started developing resistance to DDT before it was banned. And the pesticides that still work aren't always immediately effective and often need several applications over several days or more.

Limited resources

Public health departments often have limited resources to help control bedbugs. Hotel owners are reluctant to report infestations because of the negative publicity. And in apartment buildings, tenants and landlords often can't agree on who is responsible for taking care of the problem.

"It takes every one of us working together to control this problem," said Dr. Johnson Ojo, the principal health inspector for the San Francisco Department of Public Health, who specializes in bedbug infestations. "Control is very difficult, so you don't want it to become a huge problem before you deal with it.

"But you don't want to create hysteria," he said. "People should not be afraid. They just need to be very vigilant."

Bedbug prevention

It is not easy to prevent bedbug infestations, but there are precautions people can take to protect themselves from bringing bedbugs home with them and to make the extermination process easier.

-- When staying at a hotel, immediately look for signs of bedbugs, especially in and around the bed. Pay close attention to the seams of the mattress, and look behind picture frames and under telephones and lamps. Look for actual bugs or signs that they've been there, including small, dark spots. If you find bedbugs, immediately ask for a new room.

-- Keep your luggage away from the hotel bed. The bathroom may be the best place for it - that room probably gets the most thorough cleaning between occupants.

-- When you get home, vacuum your luggage. Wash and dry all of your clothes on the highest heat setting.

-- At home, buy a cover for your mattress and box spring that is specifically designed to protect from bedbugs. This won't keep bedbugs out of your home, but it will keep you from having to throw out your mattress if you have an outbreak.

-- Bedbug infestations don't have anything to do with cleanliness, but a lot of clutter in a home gives them more places to hide, and can make them more difficult to get rid of.

-- Never bring home mattresses, bed frames or upholstered furniture that has been discarded by someone else.